Many types of printing systems include one or more printheads that have arrays of marking elements that are controlled to make marks of particular sizes, colors, etc. in particular locations on the recording media in order to print the desired image. In some types of printing systems the array of marking elements extends across the width, and the image can be printed one line at a time. However, the cost of a printhead that includes a page-width array of marking elements is too high for some types of printing applications, so a carriage printing architecture is used.
In a carriage printing system (whether for desktop printers, large area plotters, etc.) the printhead or printheads are mounted on a carriage that is moved past the recording medium in a carriage scan direction as the marking elements are actuated to make a swath of dots. At the end of the swath, the carriage is stopped, printing is temporarily halted and the recording medium is advanced. Then another swath is printed, so that the image is formed swath by swath. In a carriage printer, the marking element arrays are typically disposed along an array direction that is substantially parallel to the media advance direction, and substantially perpendicular to the carriage scan direction.
In some types of printers, such as inkjet printers, the face of the printhead die is positioned near the recording medium in order to provide improved print quality. Close positioning of the printhead face to the recording medium keeps the printed dots close to their intended locations, even for angularly misdirected jets.
In order to provide the capability of printing across the entire width of the recording medium, and also to allow space for the carriage to decelerate and stop before changing directions to print the next swath, typically the carriage moves the printhead beyond the side edges of the recording medium. Generally, the position of the recording medium relative to the printhead face is fairly well controlled. However, occasionally a sheet of recording medium can have a dog-eared edge. Also occasionally multiple sheets of recording medium can be inadvertently fed at the same time, sometimes relating in paper jamming and folding in accordion fashion. In such situations, the close proximity of the printhead face to the nominal position of the recording medium can result in recording medium striking the face of the printhead as the carriage moves the printhead past the edge of the recording medium. For printhead faces made of material that is fragile or brittle, such strikes can cause catastrophic damage to the printhead, requiring its replacement.
U.S. Pat. No. 6,206,499 describes a head cover that overlaps the sides of the edges of the printhead die in order to prevent the nozzle plate being damaged due to “paper stacking”. However, there is no mention of the effectiveness of the head cover against damage of the printhead face due to folded or dog-eared edges of recording medium. In addition, the head cover described in '499 is an additional discrete part which must be separately made and assembled into the printhead.
A cost-effective mounting assembly for printhead die is thus required that will provide protection of the face of the printhead die against strike damage due to a wide range of recording medium feeding problems for printers where the printhead face is positioned close to the recording medium.